In many technical applications signals have to be received, processed and then afterwards transmitted. In addition to the desired steps of processing or transforming the received signal is also subject of undesired processes which can produce unwanted distortions in the signal to be transmitted. These distortions may have linear or non-linear form.
To avoid or reduce these signal distortions in the process of processing or even in the process of transmitting a received input signal as an output signal, different methods of equalizing input signals in advance with respect to the signal distortions to occur have been suggested. A basic principle behind these ideas is to perform a step of preprocessing the received input signal and to add certain characteristics to said input signal which annihilate or compensate the distortions which are added in the main processing step and/or transmission step.
A major drawback of known concepts of equalizing input signals is that in many cases the preprocessing steps are based on an inverse of a transfer function or on an approximation thereof, the transfer function characterizing the respective processing unit. In many cases, the particular structure of the transfer function is not known and/or the respective inverse of said transfer function cannot be established in a simple and reliable manner.